The invention relates to an instrument panel having an integrated, swing-open air-bag cover, and a process for producing such an instrument panel.
A passenger air bag in a motor car is arranged in a folded state behind an instrument-panel surface. The instrument panel exhibits a shaped stiffening panel which may be covered over with foam to dampen impact forces in the direction of the occupant and in which there is provided an unfolding opening through which the activated air bag unfolds in the direction of the passenger seat. When the air bag is in the folded state, the unfolding opening is covered over by an air-bag cover which is formed as an integral part of the instrument-panel surface and, for the most part, is separated off from the stiffening panel of the instrument panel by a separating operation and which then is swung open around a remaining connecting section when the airbag unfolds.
European Patent Document EP O 582 443 A1 discloses a steering wheel with a driver airbag which is covered over by an air-bag cover which is designed as part of the covering of the steering-wheel cup. The covering exhibits peripheral perforations which predetermine the opening line for a swinging-open movement of two cover halves when the air-bag unfolds. The air-bag cover exhibits a reinforcement panel on the inside. In the hinge region of each cover half, a nylon fabric is attached on the reinforcement panel, which fabric is encapsulated or foam-surrounded together with the reinforcement panel and is consequently held on the latter. The problem of the easily producible fastening, not achieved here, of the fabric with cost-effective manufacturing of the air-bag cover does not have the same implications here as in the case of the covering of a passenger air-bag. This is so, since the air-bag receiving means and the air-bag cover in the steering wheel are components which, in terms of material selection and configuration, do not have any decisive influence on the surrounding parts, as is the case with accommodation in the instrument panel, but can be configured individually and designed for loading in accordance with requirements. The fabric strip can thus be fastened with any suitable means.
In European Patent Document EP O 370 613 B1, a description is given of an air-bag unit for a vehicle steering wheel, in the case of which unit the air-bag cover, as part of the covering of the steering-wheel cup, remains connected on one side to the surrounding surface and is bent open around this side edge by the unfolding air-bag. In order, in this arrangement, to prevent the cover from breaking at this edge due to the loading and then being flung into the interior of the vehicle, the air-bag flap has to be manufactured here, along with the entire surrounding surfaces, from a material which can fulfil the requirements of resistance to fracture and flexural elasticity, as a result of which the entire component becomes expensive.
In the designs of German Patent Documents DE 20 45 245 Al and DE 39 18 281 Al, the air-bag cover adjoins the instrument panel in one piece and likewise exhibits the reinforcement insert thereof on the inside. An additional reinforcement of the hinge region is not provided here, for which reason the instrument panel here likewise has to be designed, in terms of material selection and structure, in accordance with the stressing of the air-bag cover.
In an exemplary embodiment according to German Patent Document DE 43 11 241 C1, the air-bag cover can be fully separated from the instrument panel, but the air-bag cover has to be connected to the instrument panel via a restraining strap, which is to be additionally manufactured and mounted, in order that the air-bag cover is not thrown far into the interior.
An object of the invention comprises attaching an air-bag cover of the generic type on the instrument panel in a secure manner, in order to minimize the manufacturing outlay.
This object is achieved by providing an arrangement wherein the reinforcement is secured on the stiffening panel by a pressing operation in which the material of the stiffening panel is pressed into the openings of the reinforcement.
Being pressed onto the connecting section, the reinforcement, with said connecting section, secures the swing-open air-bag cover on the instrument panel. In this arrangement, an intimate connection is produced by the material of the stiffening panel flowing into the openings of the reinforcement. The secure attachment of the air-bag cover onto the surrounding instrument panel is, in addition, promoted by taking the reinforcement up to the separating line and to both sides thereof, since the reinforcement material prevents further tearing at the ends of the separating line. The reinforcement may consist of sheet metal, flat-woven material or a textile insert according to various preferred embodiments of the invention. A uniform arrangement of the openings, which can be produced by a simple punching operation, also achieves a uniform connection between the stiffening panel in the air-bag cover, and in the surrounding instrument panel, and the reinforcement. The process for manufacturing the instrument panel with this reinforcement is particularly cost-effective if the shape of the stiffening panel as well as the equivalent shape of the reinforcement and, at the same time, also the connection of the two parts are produced in one pressing operation. Alternatively, both the stiffening panel and the reinforcement may be preformed before the pressing operation. Or, either the stiffening panel or the reinforcement may be preformed before the pressing operation, with the other being shaped during the pressing operation. There is no need for any additional fastening material.
This type of reinforcement renders superfluous the additional retaining straps which are intended to retain the air-bag cover on the instrument panel when the air-bag unfolds. A shaping of the instrument panel to increase the rigidity is not necessary since the reinforcement need only be arranged in the location in which it is necessary.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.